The Exoplanet Characterisation Observatory, EChO, is a dedicated space mission to investigate the physics and chemistry of Exoplanet atmospheres. Using the differential spectroscopy by transit method, it provides simultaneously a complete spectrum in a wide wavelength range between 0.4μm and 16μm of the atmosphere of exoplanets. The payload is subdivided into 6 channels. The mid-infrared channel covers the spectral range between 5μm and 11μm. In order to optimize the instrument response and the science objectives, the bandpass is split in two using an internal dichroic. We present the opto-mechanical concept of the MWIR channel and the detector development that have driven the thermal and mechanical designs of the channel. The estimated end-to-end performance is also presented.
In this paper, we present the design of the MWIR channels of EChO. Two channels cover the 5-11 micron spectral
range. The choice of the boundaries of each channel is a trade-off driven by the science goals (spectral features of key
molecules) and several parameters such as the common optics design, the dichroic plates design, the optical materials
characteristics, the detector cut-off wavelength. We also will emphasize the role of the detectors choice that drives the
thermal and mechanical designs and the cooling strategy.